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WO1998053975A1 - Moulage par injection de polymeres thermoplastiques - Google Patents

Moulage par injection de polymeres thermoplastiques Download PDF

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Publication number
WO1998053975A1
WO1998053975A1 PCT/GB1998/001590 GB9801590W WO9853975A1 WO 1998053975 A1 WO1998053975 A1 WO 1998053975A1 GB 9801590 W GB9801590 W GB 9801590W WO 9853975 A1 WO9853975 A1 WO 9853975A1
Authority
WO
WIPO (PCT)
Prior art keywords
cavity
core
tool
mould
moulding
Prior art date
Application number
PCT/GB1998/001590
Other languages
English (en)
Inventor
Roderick Michael De'ath
Original Assignee
Kontor Moulding Systems Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to AU76684/98A priority Critical patent/AU7668498A/en
Application filed by Kontor Moulding Systems Limited filed Critical Kontor Moulding Systems Limited
Priority to GB9928063A priority patent/GB2340788A/en
Publication of WO1998053975A1 publication Critical patent/WO1998053975A1/fr

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
    • B29C45/17—Component parts, details or accessories; Auxiliary operations
    • B29C45/46—Means for plasticising or homogenising the moulding material or forcing it into the mould
    • B29C45/56—Means for plasticising or homogenising the moulding material or forcing it into the mould using mould parts movable during or after injection, e.g. injection-compression moulding
    • B29C45/561—Injection-compression moulding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
    • B29C45/17—Component parts, details or accessories; Auxiliary operations
    • B29C45/46—Means for plasticising or homogenising the moulding material or forcing it into the mould
    • B29C45/56—Means for plasticising or homogenising the moulding material or forcing it into the mould using mould parts movable during or after injection, e.g. injection-compression moulding
    • B29C45/561—Injection-compression moulding
    • B29C2045/563—Enlarging the mould cavity during injection
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
    • B29C45/17—Component parts, details or accessories; Auxiliary operations
    • B29C45/46—Means for plasticising or homogenising the moulding material or forcing it into the mould
    • B29C45/56—Means for plasticising or homogenising the moulding material or forcing it into the mould using mould parts movable during or after injection, e.g. injection-compression moulding
    • B29C45/561—Injection-compression moulding
    • B29C2045/5635—Mould integrated compression drive means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
    • B29C45/17—Component parts, details or accessories; Auxiliary operations
    • B29C45/46—Means for plasticising or homogenising the moulding material or forcing it into the mould
    • B29C45/56—Means for plasticising or homogenising the moulding material or forcing it into the mould using mould parts movable during or after injection, e.g. injection-compression moulding
    • B29C45/561—Injection-compression moulding
    • B29C2045/5645—Resilient compression means

Definitions

  • the invention relates to a process for the injection moulding of thermoplastic polymers.
  • molten polymer material is injected into one or more cavities defined by separable mould parts, allowed to cool and solidify and extracted after the mould parts are separated.
  • Thermoplastic polymers shrink on cooling and this causes sink marks apparent on the surface at regions where the article is thicker than in neighbouring regions.
  • a difficulty with the above described method is that gas flow through the melt is restricted and often cut off at narrow regions of the melt since these usually solidify first.
  • the method is therefore not suitable for some forms of article and in particular may not be suitable for multi-cavity moulds for moulding multiple parts since variation in gas passage profile would cause inequality in part material.
  • the object of the invention is to provide a method of making injection moulded articles in which the risk of post-mould distortion is minimized or removed completely.
  • the present invention provides a method of injection moulding which consists in injecting molten thermoplastic polymer material into a cavity having walls defined by at least two separable mould parts, allowing the thermoplastic polymer material to cool and solidify in the cavity in a cooling phase, separating the mould parts and extracting the solidified material characterized in that one of the mould parts is capable of movement relative to the other mould parts with which it defines the walls of the said cavity and in a direction away from and towards the cavity, and in that the injection of molten thermoplastic polymer material is continued until the movable mould part is caused to move to a position away from the cavity by pressure created in the cavity by the injection thereinto of thermoplastic polymer material and wherein as the thermoplastic polymer material in the cavity undergoes shrinkage on cooling the movable mould part is caused to move towards the cavity thus maintaining contact with and pressure on the injected material in the cavity.
  • the method of the invention makes use of a mould formed by at least two separable mould parts.
  • the mould parts define the walls of the cavity into which the molten thermoplastic polymer material is injected.
  • the mould parts during the moulding operation are rigidly mounted although they are capable of being separated to enable removal of the moulded article.
  • one of the mould parts typically a core member, is capable of movement relative to the other mould parts which, together with the movable mould part, define the walls of the cavity.
  • the extent of the movement of which the movable mould part is capable is between two positions; a forward position in which the movable mould part is normally located, for instance when the molten thermoplastic polymer material is injected into the cavity until the cavity is substantially filled up to which point the pressure exerted on the contents of the cavity by the material being injected thereinto by the injection moulding machine is less than a bias applied to the moveable mould part to maintain it in its forward position and a rearward position in which the movable mould part is located when, during overfilling of the cavity, further molten thermoplastic polymer material is injected into the cavity after the cavity has been substantially filled at which time the pressure exerted on the contents of the cavity by material being injected thereinto by the injection moulding machine is greater than a bias applied to the movable mould part towards its forward position.
  • the distance of movement between the two positions will be from 2 to 3% of the mean panel thickness of the part to be moulded.
  • the distance through which the movable mould part is movable i.e., the distance between its forward and rearward positions, would be approximately 0.06mm and 0.09mm.
  • the movable mould part is, throughout the moulding operation, urged towards the forward position by resilient urging means, for example, by one or more metal springs, elastomeric spring elements, hydraulic cylinders or a combination of any of these.
  • resilient urging means for example, by one or more metal springs, elastomeric spring elements, hydraulic cylinders or a combination of any of these.
  • the moulding cycle is as follows.
  • the core member At the commencement of the cycle the core member is pushed to its forward position by the resilient urging means. In this position the gap between the core member and the mould cavity will be substantially slightly less than the desired panel thickness of the finished cooled moulded part.
  • thermoplastics material on the cavity side of the core member is, at this stage, greater than the pressure exerted externally on the core member by the resilient urging means such that the core member is moved to its rearward position against the action of the resilient urging means.
  • the injection of this additional thermoplastics material into the cavity also exerts pressure on the cooling and solidifying thermoplastics polymer material in the mould cavity such that it is urged against the opposing wall of the cavity where sink marks would otherwise be experienced.
  • the cavity is effectively "over-filled” by about 2-3% and is expected to take approximately 3% of the normal cavity filling time, i.e., from 0.1 to 0.3 seconds.
  • thermoplastic polymer material is of the order of 50 to 200 bar depending on the polymer material used and the intended final use of the moulding. Thus, the normal packing or hold phase of conventional injection moulding is not required.
  • the movable core member is maintained in contact with, and continues to exert pressure on, the cooling polymer material as the latter undergoes shrinkage in the cavity for the whole of the cooling cycle of the mould, i.e., until the mould opens and the part is ejected.
  • the pressurised intimate contact of the elements of the mould tool which are preferably water-cooled, heat is extracted from the moulding such that this moulding will rapidly cool to a low temperature at which plastic flow is prevented. Localised shrinkage marks are, thus, eliminated and 'post mould' shrinkage will be minimised.
  • a moulding tool for use in manufacture of injection moulded articles using a molten thermoplastic polymer material, the tool having at least one cavity defined by at least two separable tool parts, characterised in that one of the tool parts is movable relative to the other tool parts with which it defines the cavity and in a direction away from and towards the cavity and in that the moulding tool also comprises resilient urging means which exert pressure on the movable tool part to urge the said part towards the cavity, the movable tool part being movable away from the cavity, during operation of the moulding tool, under the action of molten thermoplastic polymer material being injected into the cavity after the filling thereof.
  • the movable tool part is capable of movement between two positions, i.e., a forward position in which the tool part is normally located under the action of pressure exerted thereon by the resilient urging means and a rearward position in which the tool part is located under the action of pressure, greater than that exerted by the resilient urging means, exerted on the tool part from the cavity side by pressurised molten thermoplastic polymer material.
  • the distance of movement between the forward position and the rearward position will be 2 to 3% of the mean panel thickness of the part being moulded by the moulding tool.
  • hollow thick-walled articles are formed by defining a cavity between a central core and an outer mould.
  • the polymer shrinks on to the core and loses thermal contact with the outer mould. Consequently, heat must be extracted via the core and because the core size is small and thermal access is restricted the cooling rate is limited. In turn this limits the cycle time of the moulding process.
  • the present invention makes it possible to arrange for the overfilling of a cavity with molten thermoplastic polymer material to urge the polymer melt to contact the outer mould and away from the core, thereby retaining thermal contact between the polymer and the outer mould as the polymer cools.
  • the core is brought into intimate contact with and to exert pressure on the cooling polymer melt to ensure that heat can be extracted from the polymer not only via the outer mould but also via the core in order to enable rapid cooling of the polymer.
  • the invention is particularly useful to the production of injection moulded articles which are substantially flat or which have flat portions since both sides of the moulding can be cooled rapidly while it is still in the mould. Problems arising from cooling a moulding mainly on one side, as in prior art apparatus, can be overcome.
  • a moulding tool for the injection moulding of generally flat thermoplastic polymer articles, the tool having a cavity defined between a core and mould characterised in that the core is movable relative to the mould and in a direction away from and towards the cavity and in that the moulding tool also comprises resilient urging means which exert pressure on the core to urge the core towards the cavity wherein the core is movable away from the cavity, during operation of the moulding tool, under the action of molten thermoplastic polymer material being injected into the cavity after the filling thereof.
  • FIGURE 1 is a cross-sectional view of part of one embodiment of a moulding tool of the present invention
  • FIGURE 2 is an expanded cross- sectional view of part of a second embodiment of a moulding tool of the presentation.
  • FIG. 1 there is shown a moulding tool 1 which is designed for moulding an article 2 formed in the cavity 3.
  • the tool comprises a cavity plate 4 and a core 5 which are separable and which together define the shape of the cavity.
  • the core is slideable in a core ring 6 such that it is capable of movement between a forward position determined by the edge 7 of the core ring and a rearward position determined by a core stop 8 which is located rearward of the core.
  • the core is biased in its forward position by resilient urging means 9.
  • the resilient urging means comprises one or more elastomeric springs although other types of urging means such as metal springs or hydraulic cylinders can be used instead of elastomeric springs.
  • the resilient urging means should, however, be such that the core is always biased to its forward position.
  • the core 5 and the core ring 6 are slidable in relation to one another. It is essential, during all phases of the moulding cycle, that the physical gap between the core and the core ring is kept to a minimum to prevent the ingress of molten polymer into the gap. Any such ingress of molten polymer would solidify in the gap and this could prevent the correct operation of the slidable core and/or cause faults on the plastics moulding at this point.
  • Molten thermoplastic polymer composition is injected into the cavity 3 via a channel 10 by a screw injector (not shown).
  • the core is caused to move against the bias created by the urging means 9 in a rearward direction until it contacts the core stop 8. At this point, the core is located at its rearward position and the cavity is overfilled by 2 to 3%.
  • the effect of this is to allow the core to conduct heat away from the polymer in the cavity so that the polymer is cooled by the core as well as by the cavity plate thus ensuring rapid and consistent cooling of the injection moulding.
  • Accelerated cooling of the core may be achieved by means of cooling water being supplied to the core by a pipe system 11.
  • the moulded article 2, when cooled sufficiently can be ejected from the mould by an ejector pin 12.
  • the slidable fit between core 5 and the core ring 6 is shown to be of a parallel form, i.e., the surface of the core ring against which the core is slidable and the opposing surface of the core are vertical which is the case when the internal diameter of the core ring at its surface against which the core is slidable, is constant.
  • the fit between the core 5 and the core ring 6 is of a tapered form.
  • Figure 2 shows an expanded view of the interface between the core and the core ring.
  • the fit between the core 5 and the core ring 6 is of a tapered form.
  • the surface of the core ring against which the core is slidable tapers inwardly towards the bottom of the core ring and the opposing surface of the core is correspondingly tapered outwards the bottom of the core.
  • a tapering fit is arranged when the internal diameter of the core ring, at its surface against which the core is slidable, gradually increases in a direction away from the cavity and the width of the core correspondingly increases gradually.
  • the angle of taper will typically be in the range of from 2° to 4° depending on the movement required.
  • the core With the core in its fully forward position it is arranged that there is no gap between the core and the core ring to ensure that the core can be accurately located and, also, to prevent the ingress of molten polymer between the core and core ring during the initial filling of the cavity.
  • the molten polymer touches the tooling it will cool and form a skin of solidified thermoplastic.
  • the injection system of the moulding machine pressurizes the molten portion of the moulding in the cavity, this pressure will force the core 5 and the core back plate 5A rearwards to the core stop 8. This causes core 5 to move relative to the core ring 6 resulting in the creation of a small gap between them.
  • This gap will typically be of the order of 0.003mm in the case where the taper angle is about 4°.
  • a tooling gap of such a size does not allow the ingress of molten polymer during normal moulding operations.
  • the practical advantages of using a tapered fit between the core 5 and the core ring 6 include:
  • the major cycle benefit achieved by the present invention is derived from cooling the injected polymer material on both sides compared to just one side as in conventional techniques.
  • the size (and therefore cost) of the moulding machine is determined by the 'packing pressure' necessary to minimise 'sinks' on the part.
  • This packing pressure tends to be relatively high, because as the part cools, it becomes progressively more difficult to inject molten material into features far away from the 'gate'.
  • the melt remains relatively hot throughout the filling and overfilling phases and therefore the pressure can be a minimum.
  • the pressure can be a minimum.
  • it allows an increase in the size of part which can be moulded on a given sized machine with associated reduction in costs to the customer.
  • the size of this mark becomes a critical quality parameter.
  • the gate diameter is substantially controlled by the length of the "packing phase” required, so that the gate does not freeze. However, when using this process this consideration no longer applies and the gate diameter may be the minimum necessary to fill the part.

Landscapes

  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Mechanical Engineering (AREA)
  • Moulds For Moulding Plastics Or The Like (AREA)
  • Injection Moulding Of Plastics Or The Like (AREA)

Abstract

On décrit un procédé de moulage par injection qui consiste à injecter une matière en polymère thermoplastique fondu dans une cavité dont les parois sont délimitées par au moins deux parties de moule séparables; il consiste ensuite à laisser la matière en polymère thermoplastique refroidir et se solidifier dans la cavité pendant une phase de refroidissement, puis à séparer les parties du moule pour extraire la matière solidifée. Le procédé se caractérise en ce qu'une des parties du moule est mobile relativement aux autres parties du moule avec lesquelles elle délimite les parois de ladite cavité et sur un axe où elle peut s'éloigner ou se rapprocher de la cavité. Le procédé se caractérise en outre par le fait que l'injection de la matière en polymère thermoplastique fondu se poursuit jusqu'à ce que la partie mobile du moule soit déplacée vers une position éloignée de la cavité sous l'effet d'une pression exercée dans la cavité par l'injection de la matière en polymère thermoplastique. Ainsi, une fois la matière rétrécie par refroidissement, la partie mobile du moule est poussée vers la cavité pour y aller au contact de le matière injectée. Pour réaliser le procédé, on utilise une moule à compression comprenant au moins une cavité (3) délimitée par au moins deux parties séparables (4, 5) du moule, qui se caractérise en ce qu'une des parties du moule est mobile relativement aux autres parties avec lesquelles elle délimite les parois de ladite cavité (3) et sur un axe où elle peut s'éloigner ou se rapprocher de cette dernière. Le procédé se caractérise en outre par le fait que le moule à compression comprend également un moyen de poussée résilient (9) qui exerce une pression sur la partie mobile du moule (5) pour la pousser vers la cavité (3). Pendant le fonctionnement, cette partie mobile du moule (5) peut être éloignée de la cavité par une pression exercée dans la cavité (3) par l'injection continue du polymère en fusion après remplissage de la cavité (3).
PCT/GB1998/001590 1997-05-30 1998-05-29 Moulage par injection de polymeres thermoplastiques WO1998053975A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
AU76684/98A AU7668498A (en) 1997-05-30 1998-05-20 Injection moulding of thermoplastic polymers
GB9928063A GB2340788A (en) 1997-05-30 1998-05-29 Injection moulding of thermoplastic polymers

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GBGB9711048.0A GB9711048D0 (en) 1997-05-30 1997-05-30 Injection moulding of thermoplastic polymer
GB9711048.0 1997-05-30

Publications (1)

Publication Number Publication Date
WO1998053975A1 true WO1998053975A1 (fr) 1998-12-03

Family

ID=10813205

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1998/001590 WO1998053975A1 (fr) 1997-05-30 1998-05-29 Moulage par injection de polymeres thermoplastiques

Country Status (3)

Country Link
AU (1) AU7668498A (fr)
GB (2) GB9711048D0 (fr)
WO (1) WO1998053975A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10048861A1 (de) * 2000-10-02 2002-04-25 Krauss Maffei Kunststofftech Verfahren und Vorrichtung zum Herstellen von dickwandigen Formteilen
DE10207080A1 (de) * 2002-02-20 2003-08-28 Krauss Maffei Kunststofftech Verfahren und Vorrichtung zum Herstellen von Kunststoffformteilen
FR2886572A1 (fr) * 2005-05-27 2006-12-08 Gentex Optics Inc Procede de configuration d'un ensemble de moulage pour le moulage par injection-compression d'une lentille
US7824597B2 (en) 2001-08-27 2010-11-02 Kraussmaffei Technologies Gmbh Method and apparatus for making flat molded plastic articles

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2443826A (en) * 1944-06-23 1948-06-22 Combined Optical Ind Ltd Apparatus for the manufacture of lenses
US2781547A (en) * 1951-12-26 1957-02-19 Honeywell Regulator Co Molding procedure and apparatus
GB2050928A (en) * 1979-05-23 1981-01-14 Omnitech Inc Method and apparatus for molding ophthalmic lenses without spoilation
JPS588622A (ja) * 1981-07-08 1983-01-18 Hitachi Ltd 精密プラスチツク部品の成形方法
JPS63114614A (ja) * 1986-04-14 1988-05-19 Olympus Optical Co Ltd 射出成形用金型
JPS63160813A (ja) * 1986-12-25 1988-07-04 Olympus Optical Co Ltd 射出成形用金型
WO1990014207A1 (fr) * 1989-05-18 1990-11-29 Maus Steven M Moulage de matieres plastiques par injection a l'aide d'un creux de moule ''adaptatif''
JPH0416319A (ja) * 1990-05-10 1992-01-21 Osamu Hamada 成形金型装置
JPH05116194A (ja) * 1991-10-24 1993-05-14 Asahi Chem Ind Co Ltd 射出成形用金型及びそれを用いた射出成形方法
DE4442536A1 (de) * 1994-03-11 1995-09-14 Bayer Ag Verfahren und Vorrichtung zur Herstellung von Formteilen aus Mehrkomponentenkunststoffen

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2443826A (en) * 1944-06-23 1948-06-22 Combined Optical Ind Ltd Apparatus for the manufacture of lenses
US2781547A (en) * 1951-12-26 1957-02-19 Honeywell Regulator Co Molding procedure and apparatus
GB2050928A (en) * 1979-05-23 1981-01-14 Omnitech Inc Method and apparatus for molding ophthalmic lenses without spoilation
JPS588622A (ja) * 1981-07-08 1983-01-18 Hitachi Ltd 精密プラスチツク部品の成形方法
JPS63114614A (ja) * 1986-04-14 1988-05-19 Olympus Optical Co Ltd 射出成形用金型
JPS63160813A (ja) * 1986-12-25 1988-07-04 Olympus Optical Co Ltd 射出成形用金型
WO1990014207A1 (fr) * 1989-05-18 1990-11-29 Maus Steven M Moulage de matieres plastiques par injection a l'aide d'un creux de moule ''adaptatif''
JPH0416319A (ja) * 1990-05-10 1992-01-21 Osamu Hamada 成形金型装置
JPH05116194A (ja) * 1991-10-24 1993-05-14 Asahi Chem Ind Co Ltd 射出成形用金型及びそれを用いた射出成形方法
DE4442536A1 (de) * 1994-03-11 1995-09-14 Bayer Ag Verfahren und Vorrichtung zur Herstellung von Formteilen aus Mehrkomponentenkunststoffen

Non-Patent Citations (5)

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Title
PATENT ABSTRACTS OF JAPAN vol. 12, no. 356 (M - 745) 26 September 1988 (1988-09-26) *
PATENT ABSTRACTS OF JAPAN vol. 12, no. 424 (M - 761) 10 November 1988 (1988-11-10) *
PATENT ABSTRACTS OF JAPAN vol. 16, no. 173 (M - 1240) 24 April 1992 (1992-04-24) *
PATENT ABSTRACTS OF JAPAN vol. 17, no. 479 (M - 1471) 31 August 1993 (1993-08-31) *
PATENT ABSTRACTS OF JAPAN vol. 7, no. 81 (M - 205) 5 April 1983 (1983-04-05) *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10048861A1 (de) * 2000-10-02 2002-04-25 Krauss Maffei Kunststofftech Verfahren und Vorrichtung zum Herstellen von dickwandigen Formteilen
US7824597B2 (en) 2001-08-27 2010-11-02 Kraussmaffei Technologies Gmbh Method and apparatus for making flat molded plastic articles
EP2289686A1 (fr) 2001-08-27 2011-03-02 KraussMaffei Technologies GmbH Procédé pour produire des pièces moulées planes en matière plastique, notamment des disques en matières plastique
DE10207080A1 (de) * 2002-02-20 2003-08-28 Krauss Maffei Kunststofftech Verfahren und Vorrichtung zum Herstellen von Kunststoffformteilen
FR2886572A1 (fr) * 2005-05-27 2006-12-08 Gentex Optics Inc Procede de configuration d'un ensemble de moulage pour le moulage par injection-compression d'une lentille

Also Published As

Publication number Publication date
AU7668498A (en) 1998-12-30
GB9711048D0 (en) 1997-07-23
GB2340788A (en) 2000-03-01
GB9928063D0 (en) 2000-01-26

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